Sliding spring contacts providing electrical power to rocker arms

Patent metadata

Field	Value
Publication number	US-10731516-B2
Application number	US-201916508686-A
Country	US
Kind code	B2
Filing date	Jul 11, 2019
Priority date	Jul 13, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

A valvetrain for an internal combustion engine includes a camshaft and a rocker arm assembly. The rocker arm assembly includes an electrical device, a rocker arm, and a cam follower. A contact held to the rocker arm abuts a spring attached to a component distinct from the rocker arm assembly to form an interface. The electrical device is powered through the interface. The spring slides over the contact as the rocker arm assembly pivots to actuate a moveable valve. The interface is formed near a pivot axis whereby the motion undergone by the interface is much less than the motion undergone by points on the rocker arm assembly more distal from the axis. Keeping the interface proximate the pivot axis and leaving the spring free to slide over the contact reducing the extent to which the spring undergoes movement and wear during valvetrain operation.

First claim

The invention claimed is:

1. A valvetrain for an internal combustion engine of a type that has a combustion chamber and a moveable valve having a seat formed in the combustion chamber, the valvetrain comprising:
a camshaft;
a rocker arm assembly comprising a rocker arm, an electrical device, and a cam follower configured to engage a cam mounted on the camshaft as the camshaft rotates;
a lash adjuster providing a fulcrum on which the rocker arm pivots to actuate the movable valve;
a contact held to the rocker arm; and
a spring attached to a component distinct from the rocker arm assembly and abutting the contact to form an interface;
wherein the spring provides power to the electrical device through the interface;
the spring is configured to slide over the contact as the rocker arm assembly pivots to actuate the moveable valve;
both the interface and a point on the rocker arm assembly distal from the interface undergoes motion as the rocker arm assembly pivots to actuate the moveable valve; and
the motion of the interface is 20% or less the motion of the point on the rocker arm assembly distal from the interface.

2. A valvetrain according to claim 1 , wherein the spring extends and contracts along a direction in which the lash adjuster extends and contracts to adjust lash.

3. A valvetrain according to claim 1 , wherein one end of the spring is attached to a framework that abuts the lash adjuster.

4. A valvetrain according to claim 1 , wherein the motion of the interface is 10% or less the motion of the point on the rocker arm assembly distal from the interface.

5. A valvetrain according to claim 1 , wherein the spring is an accordion spring.

6. A valvetrain according to claim 5 , wherein:
the accordion spring has two straight arms connected by a hoop;
the two straight arms are connected to the hoop by bends having a curvature opposite a curvature of the hoop.

7. A valvetrain according to claim 1 , further comprising a spring box that partially encloses the spring in a manner that resists twisting of the spring.

8. A valvetrain according to claim 7 , wherein the spring comprises a ribbon of metal having a face perpendicular to a wall of the spring box.

9. A valvetrain according to claim 1 , wherein the interface is formed in proximity to an axis on which the rocker arm assembly pivots to actuate the moveable valve.

10. A valvetrain according to claim 9 , wherein:
the contact comprises a ribbon of metal having a first face;
the spring comprises a ribbon of metal having a second face; and
the interface is formed by abutment between the first face and the second face.

11. A valvetrain according to claim 1 , wherein the spring wraps around the contact to provide an interference fit.

12. A valvetrain according to claim 1 , wherein the spring forms a hoop around the contact.

13. A valvetrain according to claim 1 , wherein:
the spring curves to form a convex side and a concave side; and
the spring abuts the contact on the concave side.

14. A valvetrain according to claim 1 , wherein:
the contact is held within an insulating sleeve in the rocker arm; and
a lead for the electrical device is soldered to the contact.

15. A valvetrain according to claim 1 , wherein the electrical device is an electromechanical latch assembly.

16. A valvetrain according to claim 1 , wherein the spring bears down on the lash adjuster to bias the rocker arm assembly against the lash adjuster.

17. A valvetrain according to claim 1 , wherein the spring retains the rocker arm assembly on the lash adjuster.

18. A valvetrain according to claim 17 , wherein the spring is anchored to the lash adjuster.

19. A method of manufacturing an engine with a valvetrain according to claim 18 , comprising:
attaching the rocker arm assembly to the lash adjuster using the spring; and
installing the lash adjuster with the attached rocker arm assembly in the cylinder head of an engine.

20. A valvetrain for an internal combustion engine of a type that has a combustion chamber and a moveable valve having a seat formed in the combustion chamber, the valvetrain comprising:
a camshaft;
a rocker arm assembly comprising a rocker arm, an electrical device, and a cam follower configured to engage a cam mounted on the camshaft as the camshaft rotates;
a contact held to the rocker arm and presenting a contact surface parallel to and in proximity to an axis on which the rocker arm assembly pivots to actuate a moveable valve; and
a spring attached to a component distinct from the rocker arm assembly and abutting the contact surface;
wherein the spring provides power to the electrical device through the contact; and
the spring is configured to slide over the contact surface as the rocker arm assembly pivots to actuate the moveable valve.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Lee Andrew
• Campbell Michael J
• Zurface Austin Robert
• Stretch Dale Arden

Classifications

• F01L2305/00

  Valve arrangements comprising rollers · CPC title

• F01L13/0005

  Deactivating valves · CPC title

• F01L1/2405

  by means of a hydraulic adjusting device located between the cylinder head and rocker arm · CPC title

• F01L1/245

  Hydraulic tappets · CPC title

• F01L1/185 Primary

  Overhead end-pivot rocking arms · CPC title